Smoking remains one of the major health risks in society today. This treatment development project will develop and evaluate a novel approach to smoking cessation, using a prompt intervention for those smokers who have a smoking lapse during the first two post-cessation weeks. The model is based on previous observations that an early smoking lapse is a powerful predictor of failure of the smoking cessation attempt. In this ongoing treatment development project, smokers are closely monitored during their quit attempt, and those who lapse during the early critical weeks are identified. Contingency management, which has strong empirical support for the treatment of drug abuse and addiction, will be developed and evaluated as an intervention for these at-risk early lapsers. During this 3-year project, (1) an open pilot study will be conducted to initiate and develop the contingency management therapy, specifying the optimal parameters of the approach for this project. (2) Next, the contingency management intervention will be evaluated in a well-controlled small sample (n=50) pilot study in which lapsers are randomly assigned to contingency management or a control condition with no special intervention after the post-cessation lapse. (3) The relationship between such factors as early post-cessation withdrawal symptoms, craving, mood, lapse and relapse will be examined, and potential predictors of lapse and relapse will be identified. In addition to developing and evaluating a novel treatment for smokers at high risk for relapse, this exploratory project will provide data that will contribute to a better understanding of the factors that may predict lapse and relapse. The novel concept is to ensure more reliable early post-cessation abstinence, without which long-term success appears unlikely, by proactively intervening with those who do have an early smoking lapse in an attempt to improve their prognosis. Therapeutic procedures that reduce or reverse the detrimental effects of early lapse, or interrupt the course to relapse could be a significant breakthrough in improving smoking cessation rates.